Enzymatic Production of Collagen Oligopeptides from Porcine Skin and Their Structure–Activity Relationships in Anti-Aging and Skin-Whitening Effect

Collagen-derived peptides are widely studied for their potential roles in skin health and anti-aging. This study applied response surface methodology to optimize the enzymatic hydrolysis of porcine skin-derived collagen oligopeptides (PCOPs) and investigate the associations between peptide characteristics and their cellular effects. The optimized hydrolysis conditions were a solid-to-liquid ratio of 1:2, 52.3 °C, 0.9% enzyme dosage, and pH 7.0. The resulting PCOPs contained 85.77% peptides with molecular weight < 1000 daltons (Da) and 9.68% hydroxyproline. In vitro, 5 mg/mL PCOPs reduced hydrogen peroxide (H₂O₂)-induced fibroblast senescence by 39.66% and significantly (<i>p</i> < 0.05) reduced tyrosinase activity and melanin synthesis in melanoma cells (B16). Peptidomic profiling identified 52 peptides mainly derived from type I collagen, enriched in Pro-Gly motifs. Circular dichroism analysis indicated that PCOPs primarily consisted of β-sheets (35.3%) and random coils (38.9%). These results suggest that low molecular weight, high hydroxyproline content, Pro-Gly-enriched peptides, and the predominance of β-sheet/random coil structures are associated with the observed cellular effects on fibroblast function and melanogenesis.